public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
// Consider the try block and catch block so as to compute the intersection of initializations
// and
// the minimum exit relative depth amongst all of them. Then consider the subroutine, and append
// its
// initialization to the try/catch ones, if the subroutine completes normally. If the subroutine
// does not
// complete, then only keep this result for the rest of the analysis
// process the finally block (subroutine) - create a context for the subroutine
this.preTryInitStateIndex = currentScope.methodScope().recordInitializationStates(flowInfo);
if (this.anyExceptionVariable != null) {
this.anyExceptionVariable.useFlag = LocalVariableBinding.USED;
}
if (this.returnAddressVariable != null) { // TODO (philippe) if subroutine is escaping, unused
this.returnAddressVariable.useFlag = LocalVariableBinding.USED;
}
if (this.subRoutineStartLabel == null) {
// no finally block -- this is a simplified copy of the else part
// process the try block in a context handling the local exceptions.
ExceptionHandlingFlowContext handlingContext =
new ExceptionHandlingFlowContext(
flowContext,
this,
this.caughtExceptionTypes,
null,
this.scope,
flowInfo.unconditionalInits());
handlingContext.initsOnFinally = new NullInfoRegistry(flowInfo.unconditionalInits());
// only try blocks initialize that member - may consider creating a
// separate class if needed
FlowInfo tryInfo;
if (this.tryBlock.isEmptyBlock()) {
tryInfo = flowInfo;
} else {
tryInfo = this.tryBlock.analyseCode(currentScope, handlingContext, flowInfo.copy());
if ((tryInfo.tagBits & FlowInfo.UNREACHABLE) != 0) this.bits |= ASTNode.IsTryBlockExiting;
}
// check unreachable catch blocks
handlingContext.complainIfUnusedExceptionHandlers(this.scope, this);
// process the catch blocks - computing the minimal exit depth amongst try/catch
if (this.catchArguments != null) {
int catchCount;
this.catchExits = new boolean[catchCount = this.catchBlocks.length];
this.catchExitInitStateIndexes = new int[catchCount];
for (int i = 0; i < catchCount; i++) {
// keep track of the inits that could potentially have led to this exception handler (for
// final assignments diagnosis)
FlowInfo catchInfo;
if (this.caughtExceptionTypes[i].isUncheckedException(true)) {
catchInfo =
handlingContext.initsOnFinally.mitigateNullInfoOf(
flowInfo
.unconditionalCopy()
.addPotentialInitializationsFrom(
handlingContext.initsOnException(this.caughtExceptionTypes[i]))
.addPotentialInitializationsFrom(tryInfo)
.addPotentialInitializationsFrom(handlingContext.initsOnReturn));
} else {
FlowInfo initsOnException =
handlingContext.initsOnException(this.caughtExceptionTypes[i]);
catchInfo =
flowInfo
.nullInfoLessUnconditionalCopy()
.addPotentialInitializationsFrom(initsOnException)
.addNullInfoFrom(
initsOnException) // null info only from here, this is the only way to enter
// the catch block
.addPotentialInitializationsFrom(tryInfo.nullInfoLessUnconditionalCopy())
.addPotentialInitializationsFrom(
handlingContext.initsOnReturn.nullInfoLessUnconditionalCopy());
}
// catch var is always set
LocalVariableBinding catchArg = this.catchArguments[i].binding;
catchInfo.markAsDefinitelyAssigned(catchArg);
catchInfo.markAsDefinitelyNonNull(catchArg);
/*
"If we are about to consider an unchecked exception handler, potential inits may have occured inside
the try block that need to be detected , e.g.
try { x = 1; throwSomething();} catch(Exception e){ x = 2} "
"(uncheckedExceptionTypes notNil and: [uncheckedExceptionTypes at: index])
ifTrue: [catchInits addPotentialInitializationsFrom: tryInits]."
*/
if (this.tryBlock.statements == null) {
catchInfo.setReachMode(FlowInfo.UNREACHABLE);
}
catchInfo = this.catchBlocks[i].analyseCode(currentScope, flowContext, catchInfo);
this.catchExitInitStateIndexes[i] =
currentScope.methodScope().recordInitializationStates(catchInfo);
this.catchExits[i] = (catchInfo.tagBits & FlowInfo.UNREACHABLE) != 0;
tryInfo = tryInfo.mergedWith(catchInfo.unconditionalInits());
}
}
this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(tryInfo);
// chain up null info registry
if (flowContext.initsOnFinally != null) {
flowContext.initsOnFinally.add(handlingContext.initsOnFinally);
}
return tryInfo;
} else {
InsideSubRoutineFlowContext insideSubContext;
FinallyFlowContext finallyContext;
UnconditionalFlowInfo subInfo;
// analyse finally block first
insideSubContext = new InsideSubRoutineFlowContext(flowContext, this);
subInfo =
this.finallyBlock
.analyseCode(
currentScope,
finallyContext = new FinallyFlowContext(flowContext, this.finallyBlock),
flowInfo.nullInfoLessUnconditionalCopy())
.unconditionalInits();
if (subInfo == FlowInfo.DEAD_END) {
this.bits |= ASTNode.IsSubRoutineEscaping;
this.scope.problemReporter().finallyMustCompleteNormally(this.finallyBlock);
}
this.subRoutineInits = subInfo;
// process the try block in a context handling the local exceptions.
ExceptionHandlingFlowContext handlingContext =
new ExceptionHandlingFlowContext(
insideSubContext,
this,
this.caughtExceptionTypes,
null,
this.scope,
flowInfo.unconditionalInits());
handlingContext.initsOnFinally = new NullInfoRegistry(flowInfo.unconditionalInits());
// only try blocks initialize that member - may consider creating a
// separate class if needed
FlowInfo tryInfo;
if (this.tryBlock.isEmptyBlock()) {
tryInfo = flowInfo;
} else {
tryInfo = this.tryBlock.analyseCode(currentScope, handlingContext, flowInfo.copy());
if ((tryInfo.tagBits & FlowInfo.UNREACHABLE) != 0) this.bits |= ASTNode.IsTryBlockExiting;
}
// check unreachable catch blocks
handlingContext.complainIfUnusedExceptionHandlers(this.scope, this);
// process the catch blocks - computing the minimal exit depth amongst try/catch
if (this.catchArguments != null) {
int catchCount;
this.catchExits = new boolean[catchCount = this.catchBlocks.length];
this.catchExitInitStateIndexes = new int[catchCount];
for (int i = 0; i < catchCount; i++) {
// keep track of the inits that could potentially have led to this exception handler (for
// final assignments diagnosis)
FlowInfo catchInfo;
if (this.caughtExceptionTypes[i].isUncheckedException(true)) {
catchInfo =
handlingContext.initsOnFinally.mitigateNullInfoOf(
flowInfo
.unconditionalCopy()
.addPotentialInitializationsFrom(
handlingContext.initsOnException(this.caughtExceptionTypes[i]))
.addPotentialInitializationsFrom(tryInfo)
.addPotentialInitializationsFrom(handlingContext.initsOnReturn));
} else {
FlowInfo initsOnException =
handlingContext.initsOnException(this.caughtExceptionTypes[i]);
catchInfo =
flowInfo
.nullInfoLessUnconditionalCopy()
.addPotentialInitializationsFrom(initsOnException)
.addNullInfoFrom(
initsOnException) // null info only from here, this is the only way to enter
// the catch block
.addPotentialInitializationsFrom(tryInfo.nullInfoLessUnconditionalCopy())
.addPotentialInitializationsFrom(
handlingContext.initsOnReturn.nullInfoLessUnconditionalCopy());
}
// catch var is always set
LocalVariableBinding catchArg = this.catchArguments[i].binding;
catchInfo.markAsDefinitelyAssigned(catchArg);
catchInfo.markAsDefinitelyNonNull(catchArg);
/*
"If we are about to consider an unchecked exception handler, potential inits may have occured inside
the try block that need to be detected , e.g.
try { x = 1; throwSomething();} catch(Exception e){ x = 2} "
"(uncheckedExceptionTypes notNil and: [uncheckedExceptionTypes at: index])
ifTrue: [catchInits addPotentialInitializationsFrom: tryInits]."
*/
if (this.tryBlock.statements == null) {
catchInfo.setReachMode(FlowInfo.UNREACHABLE);
}
catchInfo = this.catchBlocks[i].analyseCode(currentScope, insideSubContext, catchInfo);
this.catchExitInitStateIndexes[i] =
currentScope.methodScope().recordInitializationStates(catchInfo);
this.catchExits[i] = (catchInfo.tagBits & FlowInfo.UNREACHABLE) != 0;
tryInfo = tryInfo.mergedWith(catchInfo.unconditionalInits());
}
}
// we also need to check potential multiple assignments of final variables inside the finally
// block
// need to include potential inits from returns inside the try/catch parts - 1GK2AOF
finallyContext.complainOnDeferredChecks(
handlingContext.initsOnFinally.mitigateNullInfoOf(
(tryInfo.tagBits & FlowInfo.UNREACHABLE) == 0
? flowInfo
.unconditionalCopy()
.addPotentialInitializationsFrom(tryInfo)
.
// lighten the influence of the try block, which may have
// exited at any point
addPotentialInitializationsFrom(insideSubContext.initsOnReturn)
: insideSubContext.initsOnReturn),
currentScope);
// chain up null info registry
if (flowContext.initsOnFinally != null) {
flowContext.initsOnFinally.add(handlingContext.initsOnFinally);
}
this.naturalExitMergeInitStateIndex =
currentScope.methodScope().recordInitializationStates(tryInfo);
if (subInfo == FlowInfo.DEAD_END) {
this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(subInfo);
return subInfo;
} else {
FlowInfo mergedInfo = tryInfo.addInitializationsFrom(subInfo);
this.mergedInitStateIndex =
currentScope.methodScope().recordInitializationStates(mergedInfo);
return mergedInfo;
}
}
}
